Stem roller$ (all stems)
2 papers:
CASE-2012-AhnPR- The construction of a full-scale wheel/rail roller rig in Korea (KA, JP, SR), pp. 802–803.
ITiCSE-2000-Gerhardt-Powals- Have a great lab without needing roller skates (JGP), p. 182.
CASE-2012-AhnPR
ITiCSE-2000-Gerhardt-Powals